As a result of pervasive environmental awareness, bicycle is no longer only being considered as a transportation tool, but is becoming a tool of recreation or exercise. With the recreational and/or competitive cycling continues to increase, the worldwide bicycle production set an all-time record in 2007. Over 130 million bikes were manufactured, topping the prior years by a growth rate of 3% to 5% every year. Accordingly, as the consequence of this popularity of bicycle riding, there are more and more various bicycle accessories, such as bicycle lights, coming out on the market. It is noted that the modern bicycle lights are no longer being restricted to those flash lamps for lighting and signal indication lamps for alerting, but also can be designed as LED lamps with specific patterns for mounting on bicycle wheels. Such modern bicycles with beautiful decoration of bicycle lights are becoming almost an icon of fashion statement for our modern lifestyle.
There are already many LED bicycle light devices currently available, such as those disclosed in U.S. Pat. No. 5,800,039, U.S. Pat. No. 6,072,386, U.S. Pat. No. 6,492,963, etc., in which the on/off of a LED light mounted on a bicycle wheel is controlled and timed by a controller while enabling the timing and the control of the controller to be operated according to the detection of a sensor which is arranged for detecting the positioning and speed of the bicycle wheel. Therefore, a stationary pattern can be formed by the persistence of vision effect from the movement of the LED light as it is mounted on the rotating bicycle wheel. It is noted that there are two key components must be included in each of the prior-art LED bicycle light device, which are the sensor and a power source as the sensor is used for detecting the positioning and speed of the bicycle wheel and the power source is used for powering the LED bicycle light device. As the difficulty to assemble a device can be increased with the increasing amount of components to be assembled in the manufacturing process, the overall cost and difficulty can be greatly reduced with respect to the manufacturing of the LED bicycle light device if there is a integrated component capable of acting as a power source and also detecting the positioning and speed of the bicycle wheel as the sensor. Moreover, the prior-art LED bicycle light devices usually employ battery as their power sources, that may not be environmental friendly since not only the process of battery manufacturing can produce many hazardous materials that can pollute the environment, but also the disposal of the used batteries may cause great problem to the environment protection. Thus, it is in need of a more environmental friendly power source for the LED bicycle light devices.
In addition, there are many energy harvesters for bicycles that are already available on the market, such as those disclosed in U.S. Pat. No. 6,002,187 and U.S. Pat. No. 7,275,844. The aforesaid energy harvester is designed to generate electricity utilizing the principle of electro-magnetic induction, which generally comprises: a magnet, mounted on the rim of a bicycle wheel; and a coil, fixedly secured on a bicycle frame. Thereby, when the bicycle starts to move and the bicycle wheel is being driven to rotate for bringing along the magnet to rotate therewith, there will be induction currents being generated each time when the rotating magnet moves passing through the coil. However, the induction current generated in the aforesaid manner can be used only by those devices fixedly mounted on the bicycle frame, such as a bike headlamp, since there is no way to transmit such induction current to those devices that are going to rotate with the rotation of the bicycle wheel, such as the abovementioned LED lights. Moreover, the use of the aforesaid energy harvesters for bicycles generally will cause resistance to the rotation of the bicycle wheel and thus a cyclist may have to pedal harder for riding a bike with such energy harvester.
As for those signal indication lamps for bicycles disclosed in U.S. Pat. No. 6,002,187 and U.S. Pat. No. 7,275,844 that are capable of demonstrating specific patterns, their on/off timings are controlled by a controller whereas the timing and the control of the controller is operated according to the detection of a sensor, and the whole operation is powered by batteries.